Not every Chapter of Firstborn Marines welcomed these new arrivals; the Adeptus Mechanicus is an acquisitive and controlling organisation, known to be unscrupulous in its pursuit of power. Chapters such as the Dark Angels, the Space Wolves and the Mortifactors are notoriously insular of culture, and some guard dark secrets they would risk much to keep out of the manipulative Tech-priests' databanks. Typically, the 6th and 7th Companies both comprise ten battleline squads, while the 8th Company consists entirely of close support squads and the 9th entirely fire support squads. Equally, some Chapters may furnish their Terminator Squads with transport in the form of gunships and battle tanks, and field them as swift and utterly unstoppable assault forces. The risks involved in such an action are high, for every suit of Terminator battle-plate is an irreplaceable relic, and those who wear it to battle are scarcely less valuable -- should such a force suffer heavy losses or, worse, be annihilated, their Chapter may never truly recover.

While they might be a little slow, your opponent will be forced to dedicate a considerable amount of fire to getting rid of the Aggressors before they get into combat range; a squad equipped like this will need, on average, 60 (!) bolter shots to shift. Though they now stand a step above their Firstborn Astartes brethren, all Primaris Space Marines are still created using the original gene-seed of one of the Loyalist primarchs, like all other members of the Adeptus Astartes. Each member of an Intercessor Squad carries some variant of a Bolt Rifle, the standard Mark II Cawl Pattern version of which has a longer range and greater armour penetration than the older pattern bolter. Additionally, each Intercessor also bears a Bolt Pistol and Frag and Krak Grenades. Well does Roboute Guilliman recall the success of single-armament Space Marine Legion squads from the era of the Great Crusade -- the combination of the focused firepower of the Intercessor Squads and the adaptability of the Tactical Squads has proven all but unstoppable. In every fortress-monastery and upon every fleet-based Chapter's flagship, the machineries of a grim and bloody future were installed and awoken. From these engines of genesis would fresh waves of Primaris initiates arise, their task to fight for the Emperor's realm.The ultimate goal of this relentless campaign is to leave the foe crippled and helpless before the advance of the main Space Marine battle line. Many others among the Firstborn have since risked their lives in such a way after witnessing the undeniable battlefield capabilities of the Primaris Space Marines in action. They are...) a perversion of the Emperor's work. He may be a rotting corpse, but he created perfection in the Legiones Astartes. I cannot imagine for a moment that some arrogant Magos Biologis will have done anything but flaw that work beyond redemption."

The Unnumbered Sons served as a reserve force for Guilliman during the Indomitus Crusade, their ranks slowly reduced by attrition and the need to replenish already-extant Chapters of the Adeptus Astartes with the new class of Primaris Space Marines. Other members of the Unnumbered Sons were eventually integrated into whole new Chapters comprised only of Primaris Astartes like their brethren. An elite, fast-moving, silent-striking force of this sort can secure victories through ambush, sabotage and assassination that a far larger army could never achieve through brute force alone.Iron Hands- This chapter gives you a 6+ feel no pain and allows you to hit on a 5+ instead of a 6+ during overwatch. This is a good way to keep them from being charged when using boltstorm guantlets, as no one is going to be willing to take 72 shots that have a 1/3 chance to hit during their assault phase. The 6th Company also trains in the use of Assault Bikes and may be deployed entirely as Bike Squads. No true son of the primarchs could long look upon the increased might of the new Primaris brothers and not wish to take up that mantle of power for themselves. They sought this agonising apotheosis not for personal glory, but because no true Space Marine would refuse greater strength, resilience and weaponry with which to protect the Imperium and slaughter their many foes. The Unnumbered Sons, officially known as the Unnumbered Sons of the Primarchs, and unofficially among themselves as the " Greyshields," were nine special formations of Primaris Space Marines created by Lord Commander of the Imperium Roboute Guilliman for service in the Indomitus Crusade. Some voices within the Imperium now worry how this new type of transhuman warrior will react to the many genetic quirks and flaws found in the gene-seed of some of the more unusual Chapters, particularly given the long history of fiascoes that have resulted from attempts to alter the Emperor's original work.